CRITICS OF THE MX missile make some valid points:

MX is the brainchild of wrong-headed thinking about nuclear war. It is born of the utopian thought that we can deter the Soviets by adding megatonage to our arsenal without figuring out what we want to do with it. The MX is too big and has too many warheads, and it probably has to be based in stationary silos that cannot be hidden or fully protected.

Nonetheless, it is critical that we press ahead to build and deploy some MXs. This is the only weapon close to production that could really save American lives in the event of nuclear war.

The Congress must stop dawdling with a "maybe yes, maybe no, or maybe later" approach to this missile as the Soviets relentlessly build strategic weapons according to clear military priorities: to protect themselves and defeat the United States by destroying American weapons.

Arms controllers must stop dreaming about making the problem of the Soviet threat magically disappear. The United States does not need another ineffectual arms-control treaty. We need not only the MX but a new generation of smaller, mobile, concealable and invulnerable missiles. We need antimissile missiles and space-based lasers to destroy incoming weapons in any nuclear exchange.

We need hardware based on hard-headed realizations that we must offer our people some prospect of survival if the horrors of nuclear war are visited upon us.

Today, our nation's safety continues to deteriorate.

The Soviet SS18, a more powerful "counterforce" weapon than the MX (meaning that it can kill enemy missiles in their silos), has been deployed for six years now.

Soviet preparations for intercepting American aircraft and missiles grow by the day. The Soviet's first-rate antiaircraft defense is being augmented by state-of-the-art equipment which may be capable of intercepting ballistic missiles as well.

In addition, the Soviets have extensively tested a new antimissile-missile system. For all we know it may be in clandestine production. The big battle-management radars for a nationwide antimissile defense already exist. Finally, the Soviets are committing vast resources to laser weapons, and, according to a national intelligence estimate quoted by The New York Times, are expected to test a space-based laser in the mid-1980s.

Soviet contingency plans and exercises are depressingly realistic. Recent exercises have practiced attacks on American strategic forces on the ground with SSl8s. The Soviets also practice intercepting whatever American warheads survive and are launched. All of this means that as the months and years pass, as the Soviets become better able to threaten us and protect themselves, the costs of a possible military confrontation fall for the Soviet Union, and rise for the U.S.

On our side, the pace of innovation for strategic weapons has slowed to a crawl, while the Pentagon neglects every proposal for protecting the U.S. population against Soviet strategic weapons. Worse, we do not seem to proceed from a coherent design of what we might do, if worse came to worst, to protect ourselves and defeat the enemy.

This is because, since the days of Robert McNamara, the Pentagon has not conceived and presented strategic weapons with the seriousness they deserve. Instead, it has conceived and built them as means of threatening the Soviet Union with a certain level of damage, and therefore as assurances that the Soviets will neither attack nor blackmail us.

This was well enough so long as Soviet strategic forces were inferior to ours. But today, when one-fifth of the Soviet Union's missile force can deliver more explosive power than all our strategic forces, and as Soviet defensive preparations grow, we must think differently. We must ask what we would do if the Soviets threatened -- or tried -- to take out most of our forces with a small portion of theirs, saving the rest for coercion?

Many would have us believe that these questions will never arise, because the Soviet leaders would never find it in their interest to risk the survival of their society by threatening or carrying out such an attack. But what if, as the evidence suggests, the Soviets really mean to take advantage of a situation in which they can threaten us while protecting themselves? Then what good would our weapons do us in a crunch?

Fundamentally, we have to choose between two ways of looking at nuclear weapons, two ways of trying to ensure that we never have to go to war; either we regard them as doomsday machines with which to threaten the Soviet Union with a certain level of damage, or as tools we can use to provide for our own safety if we are ever attacked. The Pentagon has largely chosen the first alternative.

One reason for this is that many officials fear the American people would be too frightened if their leaders talked of weapons as things which might someday be used. The Pentagon thinks that Americans, like so many children, want to be reassured that war won't happen, and that the MX will help make sure it won't. Thus the gimmicky name "Peacekeeper."

This disrespect for the people's good sense is altogether out of place in a democracy. Americans want to be protected, and sense when they are not. The American people do not demand to be sedated by utopian reassurances. Rather, in big things like strategic weapons, as in little ones, they ask "What's it good for?" "What will it do for me?"

During the debate over the MX, the Pentagon should have given the American people the hard truth that this country desperately needs counterforce missiles like the MX because, despite our best efforts, we might someday be attacked. In that case, every American counterforce missile would save coutless American lives.

The Pentagon's handling of the MX is a vivid example of its disregard for both strategic and political reality. MX was conceived and pushed with little understanding of what good it might do for the country if and when it ever has to be used. In 1973 the Department of Defense committed itself to the 10- warhead, 200,000 pound MX as a means of counterbalancing the Soviet Union's deployment of heavy missiles. This monster-sized missile is one of the bad results of the strategic arms limitation (SALT) process, which was supposed to cap the arms race by limiting the number of missile silos on both sides.

Arms-control advocates believed that, with the number of launchers limited, the strategic relationship between the U.S. and the Soviet Union would remain stable indefinitely; each could do grievous harm to the other's population, but neither could protect itself by attacking the other side's missiles.

For years, fixed land-based missiles in general, and the MX in particular, were thought to be "survivable" -- and SALT was thought viable -- because the national intelligence estimates were saying that the Soviets were not even trying to develop multiple warhead missiles capable of destroying our silos.

They were wrong. By 1978, when the evidence forced the U.S. intelligence community to admit that the Soviets had developed multiple warheads with accuracies sufficient to destroy our missiles in their silos, the Carter administration and the U.S. Air Force should have reevaluated their understanding of Soviet strategy and their commitment both to the MX and to the SALT process.

In my view there is no longer any technical argument against the proposition that the Soviets -- and modern technology -- will keep our land-based missiles vulnerable so long as they are in known positions.

Some have asserted that the Soviets would be deterred from trying to exploit our vulnerability because of uncertainties about their own technical abilities to conduct a coordinated, accurate attack against our missiles. These assertions should not be taken seriously. Many experts believe that the Soviets long ago solved the technical difficulties involved in such an attack. Moreoever, they believe it is dangerous to rely on the hope that something doable will not be done.

U.S. defense planners have failed to draw the logical conclusions from the Soviets' growing ability to carry out a disarming strike less because of technology than because of their utopian belief that the Soviets are interested in stability, and of course to the bureaucracy's attachment to its own ongoing programs.

Since 1978, we have witnessed a series of attempts to do the impossible: to find a means by which our valuable, relatively immobile MX missile could survive in known locations. The American people have been asked to believe that if only the right basing mode could be found, the "ideal" situation of the 1960's would be reestablished, and the balance of terror would remain stable forever.

Not surprisingly, every proposal to do this has been found seriously flawed, and has led the American public to think of MX as an expensive fixation.

The bureaucracy's approach to strategic weapons has proved to be unsound not only strategically, but also politically. It has gone a long way toward destroying the American people's faith in their government's ability to defend them. The rest of us, however, are not obliged to follow this foolish path.

Rather, if we look at strategic weapons not as doomsday machines but realistically, even the MX has some limited, but very real, usefulness. All of our other strategic weapons were designed for more or less soft targets, i.e., to kill Russians. But the MX, with the 475-kiloton warhead and accuracy better than Minuteman's one-tenth of a mile, would have an excellent chance of destroying not more Russian people -- which should not be our objective in any event -- but the Soviet missiles which threaten us.

As for the much-maligned Dense Pack, its untouted virtue is that, by forcing attacking warheads to pass through a narrow point in space and time, it makes possible an effective, relatively simple ballistic missile defense. An antimissile missile need only hit one spot in space to defend a whole missile field.

We must finally recognize that the flaws of Dense Pack, and of every other deployment scheme for land-based missiles, exist because increasing Soviet missile accuracy has narrowed our strategic options. Since nothing fixed and undefended can resist modern attacks, land-based missiles either must be launched on warning or must be made mobile. Launch on warning is too dangerous, too prone to error. So we must go mobile.

It was downright silly to put so many counterforce warheads on a single missile, and thereby to make the MX too big to move and hide easily. So, while we build a few MXs, we should be working quickly to build many small, mobile, hideable, highly accurate single-warhead ICBMs. By 1988 we could have a fleet of invulnerable missiles which, if we ever had to use them, would drastically reduce the Soviets' ability to do us harm.

Let us realize, however, that, useful as these counterforce missiles would be, they would not change the dread fact that, as a result of their enormous build-up during the past 15 years, the Soviets can still threaten to do more harm to our forces than we do to theirs. Also, because the Soviets have so many operating production lines for long- range missiles, the chances are great we will never be able to correct this imbalance by outbuilding them.

We should also realize that there is evidence that the Soviets are moving toward basing an ever-larger proportion of their ICBM force on mobile launchers. Our counterforce missiles may not be able to find them. As a practical matter, in order to minimize the number of Soviet warheads reaching the U.S., we are going to have to build systems to destroy Soviet missiles in flight.

I believe a variety of good defenses against ballistic missiles is possible. We should no more seek "the perfect" defensive system than we should seek "the perfect" basing mode for land-based missiles. None existcs. When we insist on perfect solutions we wind up empty-handed. Rather we should build our defenses in layers, realizing a series of partial successes can add up to very substantial protection.

No defensive system, by itself, can do the whole job. If an attacker choses to waste his weapons overwhelming one part of the system, he must lighten the attack on other parts. Moreover, prudent people depend on layers of defenses. Indeed, all ground-based ABMs would function much much better if incoming attacks were thinned prior to coming into their range.

The technology of space-based lasers gives us substantial hope that attacking Soviet missiles could be defeated, or at the very least severely thinned, just after they rose out of the atmosphere.

Today, I am convinced, no informed person can any longer deny that the requisite laser power, the requisite accuracy in pointing and tracking, and the know-how for building the big space-based mirrors is in hand.

In 1980 a study for the Pentagon -- led by a man vehemently opposed to building lasers -- said that the U.S. could have a fleet of missile-killing lasers in space by 1994. The General Accounting Office, in a report released in 1982, said that the technology of space lasers was basically underfunded and that, with an intelligent increase of support, the U.S. could soon be testing a space-laser weapon.

Some have expressed fear that outer space might become militarized. This fear is misplaced. Space has been militarized for offensive purposes for a generation. We now have the choice of putting into space the means to destroy weapons of mass destruction. By building such means, we would tend to move the strategic struggle away from people, and into a realm where our technological superiority would be decisive. On what moral, political, or strategic grounds should we refuse to defend ourselves?

I'm afraid that the Department of Defense is failing to push for the several means of protecting Americans against ballistic missiles for the same reason that it preferred the MX over the small mobile counterforce missiles and for the same reason that it made the worst kind of arguments in favor of MX.

That reason is a commitment, more habitual than conscious, to the strategic utopianism of the 1960s: War can be banished forever if both the American and Soviet peoples are kept fully and forever vulnerable.

No one should be surprised, however, that both the Soviets and the American people have found this vision repelling. The Soviets, of course, are making frighteningly realistic preparations for both offense and defense. The time has arrived technically (if not intellectually) when we can focus our national effort not on greater destruction of mankind, but on the ever-greater protection of Americans from that greater destructive power.